Rotary drill mast locking mechanism

ABSTRACT

A locking mechanism for locking a mast includes a double acting cylinder having a piston coupled with a piston rod adapted to slide inside a cylinder barrel. The cylinder barrel is coupled with a first shaft through a first coupling pin. Mounting brackets coupled to a base plate of the mast guide a sliding motion of the first coupling pin, and the cylinder barrel. A first locking pin connected to the piston rod selectively engages a first side plate based on the sliding motion of the piston rod. A retraction stopper restricts a sliding motion of the first locking pin away from the first side plate, and subsequently causes a movement of the cylinder barrel towards the first end of the cylinder barrel. A second locking pin connected to the shaft selectively engages a second side plate based on the sliding motion of the cylinder barrel.

TECHNICAL FIELD

The present disclosure relates to a mechanism for locking a mast of a rotary drill. More specifically, the present disclosure relates to a mechanism having a single double acting actuator assembly emulating functions equivalent to that of two double acting actuators.

BACKGROUND

Drilling systems are generally known to include a vertical mast constructed from structural members such as steel beams and reinforcing supports. The mast is often coupled to a mobile platform which along with other components typically form a drilling rig for positioning the mast in a desired location and angular orientation to conduct a drilling operation. The mast is often equipped with a drill carousel which is structured and adapted to support a drill string formed from a combination of pipe segments (e.g., drill pipes, drill rods, drill extenders, etc.). The drill carousel is used to selectively add the pipe segments to the drill string for drilling a hole having a desired depth. The drill carousel is intended to allow a drilling operation to progress into the drill hole by making readily available a continuous string of pipe segments as needed for advancing a drilling tool into a drill hole.

Drilling operations may also require the mast to be inclined at an angle while the drilling operation is performed. The mast may need to be securely locked in an inclined position to perform the drilling operation effectively. Typically, a locking mechanism may be used to lock the mast in the inclined position. The locking mechanism is an additional safety measure in addition to hydraulically operated cylinders used for mast raising or lowering. Locking mechanisms conventionally known in the art are quite complex and include a large number of parts. Such high part count, and complexity in operation makes the locking mechanism difficult to use.

An exemplary locking mechanism may include two double acting cylinders for locking the mast. Two double acting cylinders require two sets of hose routings, two sets of sealings, two sets of mounting arrangements etc. Such a mechanism requires very high part count, and poses various challenges during service and maintenance operations owing to complexity of the locking mechanism. Thus, an improved locking mechanism is required.

SUMMARY

In an aspect of the present disclosure, a locking mechanism for locking a mast of a rotary drill is provided. The locking mechanism includes a double acting cylinder. The double acting cylinder includes a cylinder barrel having a first end and a second end. A first barrel cover is coupled to the cylinder barrel at the first end. The first barrel cover includes a cover adapted to be coupled to the cylinder barrel at the first end, and a barrel cover shaft coupled to the cover. The barrel cover shaft includes a first surface defining a first aperture. The double acting cylinder further includes second barrel cover coupled to the cylinder barrel at the second end. The double acting cylinder includes a piston which performs a sliding motion inside the cylinder barrel between the first end and the second end. The double acting cylinder includes a piston rod coupled to the piston. The piston rod slides in a first direction and a second direction relative to the second end of the cylinder barrel. The locking mechanism includes a first coupling mechanism for coupling the first barrel cover to a first shaft towards the first end of the cylinder barrel. The first coupling mechanism includes a first cover member having a first cover surface defining a first coupling pin hole, and a first shaft opening which receives the first shaft therein. The first coupling mechanism further includes a first coupling pin passing through the first coupling pin hole and the first aperture of the barrel cover shaft such that the first coupling pin couples the first cover member and the barrel cover shaft. The first coupling pin has a first end and a second end extending out from the first coupling pin hole. The locking mechanism includes a pair of mounting brackets coupled to a base plate of the mast. The pair of mounting brackets includes a first mounting bracket having a first bracket surface defining a first slot. The first slot has a first end and a second end. The pair of mounting brackets includes a second mounting bracket having a second bracket surface defining a second slot. The second slot has a third end and a fourth end. The first slot allows the first end of the first coupling pin to slide inside the first slot between the first and second ends of the first slot, and the second slot allows the second end of the first coupling pin to slide inside the second slot between the third and fourth ends of the second slot such that a sliding motion of the first coupling pin, and subsequently a sliding motion of the cylinder barrel is guided by the first slot and the second slot. The locking mechanism includes a first locking pin connected to the piston rod, and selectively engaging a first side plate based on the sliding motion of the piston rod. The locking mechanism includes a retraction stopper mounted on the base plate of the mast. The retraction stopper restricts an extent of sliding motion of the first locking pin in a second direction, and subsequently causes a movement of the cylinder barrel in the first direction. The locking mechanism further includes a second locking pin connected to the first shaft, and selectively engaging a second side plate based on the movement of the cylinder barrel. The mast of the rotary drill is locked when the first locking pin and the second locking pin are engaged with the first side plate and the second side plate respectively. The mast of the rotary drill is unlocked when the first locking pin and the second locking pin are disengaged with the first side plate and the second side plate respectively.

In another aspect of the present disclosure, a rotary drill is provided. The rotary drill includes a first side plate, and a second side plate. The rotary drill includes a mast provided between the first side plate and the second side plate, and rigidly coupled to the chassis of the machine. The rotary drill includes a base plate coupled to the mast towards a bottom end of the mast. The rotary drill includes a locking mechanism for coupling the mast with the first side plate and the second side plate. The locking mechanism includes a double acting cylinder. The double acting cylinder includes a cylinder barrel having a first end and a second end. A first barrel cover is coupled to the cylinder barrel at the first end. The first barrel cover includes a cover adapted to be coupled to the cylinder barrel at the first end, and a barrel cover shaft coupled to the cover. The barrel cover shaft includes a first surface defining a first aperture. The double acting cylinder further includes second barrel cover coupled to the cylinder barrel at the second end. The double acting cylinder includes a piston which performs a sliding motion inside the cylinder barrel between the first end and the second end. The double acting cylinder includes a piston rod coupled to the piston. The piston rod slides in a first direction and a second direction relative to the second end of the cylinder barrel. The locking mechanism includes a first coupling mechanism for coupling the first barrel cover to a first shaft towards the first end of the cylinder barrel. The first coupling mechanism includes a first cover member having a first cover surface defining a first coupling pin hole, and a first shaft opening which receives the first shaft therein. The first coupling mechanism further includes a first coupling pin passing through the first coupling pin hole and the first aperture of the barrel cover shaft such that the first coupling pin couples the first cover member and the barrel cover shaft. The first coupling pin has a first end and a second end extending out from the first coupling pin hole. The locking mechanism includes a pair of mounting brackets coupled to the base plate of the mast. The pair of mounting brackets includes a first mounting bracket having a first bracket surface defining a first slot. The first slot has a first end and a second end. The pair of mounting brackets includes a second mounting bracket having a second bracket surface defining a second slot. The second slot has a third end and a fourth end. The first slot allows the first end of the first coupling pin to slide inside the first slot between the first and second ends of the first slot, and the second slot allows the second end of the first coupling pin to slide inside the second slot between the third and fourth ends of the second slot such that a sliding motion of the first coupling pin, and subsequently a sliding motion of the cylinder barrel is guided by the first slot and the second slot. The locking mechanism includes a first locking pin connected to the piston rod, and selectively engaging the first side plate based on the sliding motion of the piston rod. The locking mechanism includes a retraction stopper mounted on the base plate of the mast. The retraction stopper restricts an extent of sliding motion of the first locking pin in a second direction, and subsequently causes a movement of the cylinder barrel in the first direction. The locking mechanism further includes a second locking pin connected to the first shaft, and selectively engaging the second side plate based on the movement of the cylinder barrel. The mast of the rotary drill is locked when the first locking pin and the second locking pin are engaged with the first side plate and the second side plate respectively. The mast of the rotary drill is unlocked when the first locking pin and the second locking pin are disengaged with the first side plate and the second side plate respectively.

In yet another aspect of the present disclosure, a method for locking a mast of the rotary drill is provided. The method includes supplying an actuating fluid to a first end of a double acting cylinder. The double acting cylinder has a cylinder barrel, and a piston rod coupled to a piston which slides inside the cylinder barrel. The method includes moving a first locking pin coupled with the piston rod to engage a first side plate coupled to the chassis through the movement of the piston rod due to force applied by the actuating fluid. The method further includes moving a second locking pin coupled with the double acting cylinder to engage a second side plate coupled to the chassis through the movement of the cylinder barrel of the double acting cylinder. The mast of the rotary drill is locked when the first locking pin and the second locking pin are engaged with the first side plate and the second side plate respectively.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a side view of a rotary drill showing a mast in two angular positions, in accordance with an aspect of the present disclosure;

FIG. 2 is a bottom perspective view of the rotary drill, in accordance with an aspect of the present disclosure;

FIG. 3 is a zoomed in bottom perspective view of a locking mechanism to lock the mast, in accordance with an aspect of the present disclosure;

FIG. 4 is a sectional view of the locking mechanism along a sectional plane A-A′ of FIG. 3, in accordance with an aspect of the present disclosure;

FIGS. 5 to 8 are the sectional views of the locking mechanism along the plane A-A′ showing a first locking pin and the second locking pin in various positions, in accordance with an aspect of the present disclosure;

FIG. 9 is a perspective view of the locking mechanism, in accordance with another aspect of the present disclosure;

FIG. 10 is a perspective view of the locking mechanism, in accordance with yet another aspect of the present disclosure;

FIG. 11 is a method flow chart for locking the mast, in accordance with an aspect of the present disclosure; and

FIG. 12 is a method flow chart for unlocking the mast, in accordance with an aspect of the present disclosure.

DETAILED DESCRIPTION

Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. FIG. 1 illustrates a side view of an exemplary machine 100 shown as a rotary drill. The machine 100 includes a chassis 102 supported over a ground engaging mechanism 104. The ground engaging mechanism 104 is illustrated as crawler tracks. However, it should be contemplated that the ground engaging mechanism 104 may be any other ground engaging mechanism as well such as wheels. The machine 100 includes an operator cab 106 supported on the chassis 102 to accommodate an operator for controlling various components and functions of the machine 100.

The machine 100 further includes a mast 108 mounted on the chassis 102. The mast 108 is illustrated in an upright position. However, the mast 108 may be coupled to the chassis 102 through a pivot mechanism (not shown) such that the mast 108 may be stored in a horizontal position over the chassis 102. The mast 108 may also tilt towards the operator cab 106 within an angular range defined by specifications of the machine 100 such as weight of the mast 108, height of the mast 108, type of terrain over which the machine 100 is operating etc. The mast 108 is also illustrated in tilted positions towards and away from the operator cab 106 through dotted lines about a pivot point 109.

During a drilling operation, the machine 100 is supported on jacks 110 for ensuring a stable position of the machine 100. The jacks 110 are provided on both front and rear sides of the machine 100. Although only one jack 110 is visible towards each of the front and rear sides of the machine 100 in FIG. 1, it should be contemplated that similar corresponding jacks 110 are provided on other side of the machine 100 to support the machine 100 during a drilling operation. The jacks 110 may be actuated by hydraulic or pneumatic means.

The machine 100 uses long straight sections of drill pipes 111 which are connected to a work head (not shown), to operate a work tool (not shown) and perform the drilling operation. The work tool may be a drill bit or a bore bit. The work head may be a rotary drill head. The work head may be mounted on the mast 108, and configured to travel up and down the mast 108 using any suitable mechanism which may be applied with various aspects of the present disclosure. An example of such a mechanism may be a cable feed system. The machine 100 includes various other components such as a dust curtain 112 to prevent dust generated due to the drilling operation from spreading in environment, a dust collector 114 for collecting the dust contained by the dust curtain 112, mufflers 116 to reduce noise, air filters 118, and a power source 120 to provide power for propulsion as well as the drilling operation etc. These components are not being discussed in detail as the present disclosure is not limited by any such components in any manner.

The mast 108 needs to be tilted as per requirements of the drilling operation. The mast 108 needs to be locked securely in tilted positions for the drilling operation to be performed safely, and in an efficient manner. FIG. 2 shows a bottom perspective view of a locking mechanism 212 of the machine 100. A base plate 202 is coupled to the mast 108 towards bottom of the mast 108. The mast 108 extends away from the base plate 202 in an upward direction. A pivot axis Y-Y′ of the mast 108 is also shown. A pair of side plates 204, 206 is coupled to the chassis 102 on opposite sides of the mast 108.

The pair of side plates includes a first side plate 204 and a second side plate 206. The first side plate 204 and the second side plate 206 may be coupled to the chassis 102 by any suitable joining mechanism such as welding, mechanical fasteners etc. The first side plate 204 has a surface 205 defining multiple openings 208. The multiple openings 208 defined on the surface 205 of the first side plate 204 are angularly spaced apart from each other. The openings 208 may be disposed along the circumference of an arc 211 whose radius may be defined by a distance between the mast's pivot axis Y-Y′ and a central axis X-X′ (shown in FIGS. 4 to 8) of a locking mechanism 212. In an embodiment, the multiple openings 208 on the surface 205 of the first side plate 204 may be spaced apart from each other by 5 degrees. The second side plate 206 also has a surface 207 defining multiple openings 210 corresponding to the openings 208 on the surface 205 of the first side plate 204. The multiple openings 210 on the surface 207 of the second side plate 206 are angularly spaced apart from each other. In an embodiment, the openings 210 defined by the surface 207 of the second side plate 206 may be spaced apart from each other by 5 degrees. The openings 208, 210 defined by the surfaces 205, 207 of the first side plate 204 and the second side plate 206 respectively, may be in line with each other, or may be spaced apart from each other in respective side plates by any other angular range as well which may be suitable for application with various aspects of the present disclosure.

The locking mechanism 212 is provided for locking the mast 108 with the pair of side plates. The locking mechanism 212 allows the mast 108 to be safely and securely locked to the pair of side plates in various angularly tilted configurations as per requirements of the drilling operation. FIG. 3 illustrates further details of the locking mechanism 212. The locking mechanism 212 includes a double acting cylinder 302. The double acting cylinder 302 may be actuated by hydraulic or pneumatic means. The double acting cylinder 302 includes a cylinder barrel 304 having a first end 306 and a second end 308. The cylinder barrel 304 includes a first opening 310 and a second opening 312 for supplying an actuating fluid to the cylinder barrel 304. The fluid lines connecting the first & second openings 310 & 312 respectively, haven't been shown for the sake of brevity.

The cylinder barrel 304 is a hollow cylindrical shaped component. The cylinder barrel 304 includes a first barrel cover 314 coupled to the cylinder barrel 304 at the first end 306. The first barrel cover 314 may seal the cylinder barrel 304 at the first end 306 to prevent any leakage of the actuating fluid from the first end 306 of the cylinder barrel 304. The first barrel cover 314 prevents any leakage of the actuating fluid. The first barrel cover 314 includes a cover 301 coupled to the first end 306 of the cylinder barrel 304. The first barrel cover 314 further includes a barrel cover shaft 303 coupled to the cover 301. The barrel cover shaft 303 has a first surface 305 which defines a first aperture 307. The first aperture 307 may be a circular opening defined at an end of the barrel cover shaft 303. The first aperture 307 may be of any other suitable shape as well. The double acting cylinder 302 further includes a piston 316 (shown in FIGS. 4 to 8) which slides inside the cylinder barrel 304 between the first end 306 and the second end 308 in a first direction (denoted by an arrow numbered as 321) and a second direction (denoted by another arrow numbered 323). A piston rod 318 is coupled to the piston 316 such that the piston rod 318 extends outwards from the second end 308 of the cylinder barrel 304. The piston rod 318 has a piston rod surface 309 which defines a second aperture 311 at an end of the piston rod 318. The second aperture 311 may be a circular opening defined at an end of the piston rod 318, towards the second end 308 of the cylinder barrel 304. The second aperture 311 may be of any other suitable shape as well. The second aperture 311 may be used to couple the piston rod 318 with any other component of the locking mechanism 212. A second barrel cover 313 is coupled to the cylinder barrel 304 at the second end 308 of the cylinder barrel 304. The second barrel cover 313 prevents any leakage of hydraulic fluid from the second end 308 of the cylinder barrel 304.

The locking mechanism 212 includes a first shaft 344 coupled to the first barrel cover 314. The first shaft 344 is coupled to the first barrel cover 314 towards the first end 306 of the cylinder barrel 304. The first barrel cover 314 may transfer motion of the cylinder barrel 304 to the first shaft 344. The first shaft 344 is coupled to the first barrel cover 314 through a first coupling mechanism 370. The first coupling mechanism 370 includes a first cover member 372. The first cover member 372 has a first cover surface 373 which defines a first shaft opening 374. The first shaft 344 is received in the first shaft opening 374. Shape and size of the first shaft opening 374 may be such that the first shaft 344 may be appropriately received in the first shaft opening 374. The first shaft 344 and the first cover member 372 may be joined together by any suitable joining mechanism such as press-fit, welding, adhesive, or by threaded engagement. The first cover surface 373 of the first cover member 372 further defines a pair of first coupling pin holes 376. The pair of first coupling pin holes 376 receives a first coupling pin 378. The pair of first coupling pin holes 376 are defined with the first cover surface 373 such that the first coupling pin 378 passes through both the first coupling pin holes 376. The first coupling pin 378 has a generally cylindrical structure extending between a first end 380 and a second end 382. The first coupling pin 378 may be designed appropriately so that the first coupling pin 378 may pass through the pair of first coupling pin holes 376, and the first aperture 307.

The first cover member 372 partially encloses the first barrel cover 314. The first cover member 372 encloses the first barrel cover 314 such that the first aperture 307 aligns with the pair of first coupling pin holes 376. The alignment of the first aperture 307, and the pair of first coupling pin holes 376 is such that the first coupling pin 378 passes through both the pair of first coupling pin holes 376, and the first aperture 307, and joins the first barrel cover 314 with the first cover member 372. Further, the first aperture 307 also includes spherical bearings 315 therein, to account for any misalignment between the first coupling pin 378 and the first barrel cover 314. As both the first barrel cover 314 and the first shaft 344 are coupled to the first cover member 372, the first barrel cover 314 and the first shaft 344 also get coupled to each other. The first barrel cover 314 may transfer an axial force to the first shaft 344 even when the first barrel cover 314 and the first shaft 344 are not in perfect axial alignment, as the first cover member 372 accommodates any misalignment between the first shaft 344 and the first barrel cover 314.

The locking mechanism 212 further includes a pair of mounting brackets. The pair of mounting brackets include a first mounting bracket 328 and a second mounting bracket 330. The first mounting bracket 328 and the second mounting bracket 330 may be coupled to the base plate 202 through any suitable joining mechanism such as welding, mechanical fasteners. In an embodiment, at least one of the first mounting bracket 328 and the second mounting bracket 330 is coupled to the base plate 202 in a removable manner by means of mechanical fasteners such as bolts. The mechanical fasteners may allow the first mounting bracket 328 and the second mounting bracket 330 to be readily uncoupled from the base plate 202 for servicing and maintenance of the locking mechanism 212. The first mounting bracket 328 and the second mounting bracket 330 may be removably coupled to the base plate 202 by means of mechanical fasteners for ease of serviceability. It should be contemplated that the first mounting bracket 328 and the second mounting bracket 330 may also be welded to the base plate 202, if required.

The first mounting bracket 328 has a first bracket surface 325 which defines a first slot 332 and the second mounting bracket 330 has a second bracket surface 327 which defines a second slot 334. The first slot 332 and the second slot 334 substantially extend across lengths of the first mounting bracket 328 and the second mounting bracket 330. The first bracket surface 325 defines the first slot 332 having a first end 336 and a second end 338. The first end 380 of the first coupling pin 378 slides inside the first slot 332 between the first end 336 and the second end 338 of the first slot 332. Similarly, the second bracket surface 327 defines the second slot 334 having a third end 340 and a fourth end 342. The second end 382 of the first coupling pin 378 slides inside the second slot 334 between the third end 340 and the fourth end 342 of the second slot 334. The first coupling pin 378 engages the first slot 332 and the second slot 334 such that the pair of mounting brackets guides a sliding motion of the first coupling pin 378. The pair of mounting brackets also restricts an extent of sliding motion of the first coupling pin 378. As the first coupling pin 378 also passes through the first aperture 307 defined by the first barrel cover 314, the pair of mounting brackets also restricts an extent of movement of the first coupling pin 378, and subsequently an extent of sliding motion of the cylinder barrel 304.

The locking mechanism 212 further includes a second shaft 384 coupled to the piston rod 318 towards the second end 308 of the cylinder barrel 304. The second shaft 384 may be coupled to the piston rod 318 in a manner such that the second shaft 384 may transfer axial force provided by the piston rod 318 through the second shaft 384. The second shaft 384 is coupled to the piston rod 318 through a second coupling mechanism 386. The second coupling mechanism 386 includes a second cover member 388. The second cover member 388 has a second cover surface 385 which defines a second shaft opening 390. The second shaft 384 is received in the second shaft opening 390. The second shaft 384 and the second cover member 388 may be joined together by any suitable joining mechanism such as press-fit, welding, adhesive etc. The second cover surface 385 of the second cover member 388 further defines a pair of second coupling pin holes 392. The pair of second coupling pin holes 392 receive a second coupling pin 394. The second cover surface 385 also defines a pair of second coupling pin holes 392 with the second cover member 388 such that the second coupling pin 394 passes through the pair of second coupling pin holes 392. The second coupling pin 394 has a generally cylindrical structure. The second coupling pin 394 may be designed appropriately so that the second coupling pin 394 may pass through both the pair of second coupling pin holes 392, and the second aperture 311 defined by the piston rod surface 309, towards the second end 308 of the cylinder barrel 304. Further, the second aperture 311 also includes spherical bearings 317 therein, to account for any misalignment between the second coupling pin 394 and the piston rod 318.

The second cover member 388 partially encloses the piston rod 318. The second cover member 388 encloses the piston rod 318 such that the second aperture 311 aligns with the pair of second coupling pin holes 392. The alignment of the second aperture 311, and the pair of second coupling pin holes 392 in the second cover member 388 is such that the second coupling pin 394 passes through both the second coupling pin holes 392, and the second aperture 311, and joins the piston rod 318 with the second cover member 388. As both the piston rod 318 and the second shaft 384 are coupled to the second cover member 388, the piston rod 318 and the second shaft 384 also get coupled to each other. The piston rod 318 may transfer an axial force to the second shaft 384 even when the piston rod 318 and the second shaft 384 are not in perfect axial alignment, as the second cover member 388 accommodates any misalignment between the second shaft 384 and the piston rod 318.

The locking mechanism 212 includes a first locking pin 354 coupled to the second shaft 384 towards the second end 308 of the cylinder barrel 304, and a second locking pin 356 connected to the first shaft 344 towards the first end 306 of the cylinder barrel 304. The first locking pin 354 may engage one of the openings 208 defined by the surface 205 of the first side plate 204, and the second locking pin 356 may engage one of the openings 210 defined by the surface 207 of the second side plate 206 to lock the mast 108. The first locking pin 354 is supported by a first guide member 358 adjacent to the first side plate 204. The first guide member 358 is mounted on the base plate 202 which forms base of the mast 108. The first guide member 358 has a first guide collar 359 having a diameter slightly greater than the first locking pin 354 such that the first guide member 358 can support the first locking pin 354 through the first guide collar 359 while sliding inside and outside of the openings 208 defined in the first side plate 204. The second locking pin 356 is supported by a second guide member 362 adjacent to the second side plate 206. The second guide member 362 is mounted on the base plate 202. The second guide member 362 has a second guide collar 363 having a diameter slightly greater than the second locking pin 356 such that the second guide member 362 can support the second locking pin 356 through the second guide collar 363 while sliding inside and outside of the opening 210 defined by the surface 207 of the second side plate 206.

The locking mechanism 212 includes a retraction stopper 366 mounted on the base plate 202 between the first guide member 358 and the double acting cylinder 302. The retraction stopper 366 may be coupled to the base plate 202 through any suitable joining mechanism such as welding, mechanical fasteners etc. The retraction stopper 366 is a plate like structure having a groove 368 to allow the second shaft 384 to slide over the retraction stopper 366. A sectional plane A-A′ parallel to vertical face of the base plate 202 passes through the locking mechanism 212.

FIG. 4 illustrates a sectional view of the locking mechanism 212 along the sectional plane A-A′ (shown in FIG. 3). A central axis X-X′ of the locking mechanism is illustrated. The sectional view shows further structural details of the locking mechanism 212. The first locking pin 354 is coupled to the second shaft 384. The first locking pin 354 has a first end 402 and a second end 404. The first locking pin 354 has a curved profile towards the first end 402 to allow easy engagement of the first locking pin 354 with the openings 208 defined by the surface 205 of the first side plate 204. The first locking pin 354 has a first hexagonal profile 406 towards the second end 404. The first locking pin 354 may also have any other profile as well which may allow holding the first locking pin 354 with a tool like a spanner for adjustment. Further, the first locking pin 354 has a cylindrical portion 355 extending between the first hexagonal profile 406 and the second end 404, such that the cylindrical portion 355 is received by the first guide collar 359 and the openings 208. A first lock nut 407 is coupled to the first locking pin 354 towards the second end 404. The hexagonal profile 406 and the first lock nut 407 together may be used to tighten the coupling between the second shaft 384 and the first locking pin 354. The first locking pin 354 further defines a threaded opening 408 towards the second end 404 to allow the second shaft 384 to be coupled to the first locking pin 354. The shaft 384 is provided with threads towards an end to engage with the first lock nut 407 and the first locking pin 354.

The second locking pin 356 has a first end 410 and a second end 412. The second locking pin 356 has a curved profile towards the first end 410 to allow easy engagement of the second locking pin 356 with the opening 210 defined by the surface 207 of the second side plate 206. The second locking pin 356 has a second hexagonal profile 414 towards the second end 412. The second locking pin 356 may also have any other profile as well which may allow holding the second locking pin 356 with a tool like a spanner for adjustment. Further, the second locking pin 356 has a cylindrical portion 357 extending between the second hexagonal profile 414 and the second end 412, such that the cylindrical portion 357 is received by the second guide collar 363 and the openings 210. A second lock nut 413 is coupled to the first shaft 344 towards the second end 412. The hexagonal profile 414 and the second lock nut 413 together may be used to tighten the coupling between the first shaft 344 and the second locking pin 356. The second locking pin 356 further defines an opening 416 towards the second end 412 to allow the first shaft 344 to be coupled to the second locking pin 356.

FIG. 4 illustrates the locking mechanism 212 with the first locking pin 354 and the second locking pin 356 not engaging the first side plate 204 and the second side plate 206 respectively. The piston 316 is adjacent to the first end 306 of the cylinder barrel 304. For locking the mast 108, the actuating fluid is supplied through the first opening 310 of the cylinder barrel 304, and retracted from the second opening 312 of the cylinder barrel 304. Subsequently, the piston 316 and the piston rod 318 are pushed towards the second end 308 of the cylinder barrel 304 in the first direction 321 due to force of the actuating fluid as shown in FIG. 5. As the piston 316 and the piston rod 318 are pushed towards the second end 308 of the cylinder barrel 304, the piston rod 318 pushes the second shaft 384. The second shaft 384 subsequently pushes the first locking pin 354 to slide through the first guide member 358, and engage with the opening 208 defined by the surface 205 of the first side plate 204, which is part of the chassis 102.

FIG. 5 shows the first locking pin 354 in a locked position such that the first locking pin 354 is engaged with the opening 208 defined by the first side plate 204. The first guide member 358 restricts further sliding motion of the first locking pin 354 towards the first side plate 204 in the first direction 321. Now, as the actuating fluid is still applying force between the piston 316 and the cylinder barrel 304 and the piston 316 cannot move any further towards the second end 308 of the cylinder barrel 304, the cylinder barrel 304 starts moving towards the first end 306 of the cylinder barrel 304 in the second direction 323. The cylinder barrel 304 slides towards the first end 306 of the cylinder barrel 304 until the second end 412 of the second pin 356 abuts with the second guide member 362. The coupling pin 378 guided by the first slot 332 and the second slot 334 facilitates back and forth movement of the cylinder barrel 304 restrictively within the first slot 332 and the second slot 334. This prevents the locking mechanism 212 from falling out from a generally straight line of motion during operation.

Typically, with a double acting actuator like the double acting cylinder 302, it is possible to transfer force in one direction with an extension stroke, and retract the applied force with the return stroke. However, as the double acting cylinder 302 is also coupled with the pair of mounting brackets 204 206, abutment of the first coupling pin 378 within the first and second slots 332, 334 respectively, and the abutment of first locking pin 354 with the retraction stopper 366 accounts for transfer of forces in two directions, i.e. in the first direction 321 and the second direction 323. Therefore, the double acting cylinder 302 essentially performs function of two double acting cylinders.

FIG. 6 shows end position of sliding motion of the cylinder barrel 304 towards the first end 306 of the cylinder barrel 304. The first coupling pin 378 reaches most extreme position possible towards the first side plate 204. As the first barrel cover 314 and the first shaft 344 are pushed towards the first end 306 of the cylinder barrel 304 in the second direction 323, the first shaft 344 subsequently pushes the second locking pin 356 to slide through the second guide member 362, and engage with the opening 210 defined by the surface 207 of the second side plate 206. The second guide member 362 restricts further sliding motion of the second locking pin 356 towards the second side plate 206 in the second direction 323. As the first locking pin 354 and the second locking pin 356 are engaged with the first side plate 204 and the second side plate 206 respectively, the mast 108 gets rigidly locked with the first side plate 204 and the second side plate 206, and hence the chassis 102.

To unlock the mast 108 from the first side plate 204 and the second side plate 206, the actuating fluid is supplied to the double acting cylinder 302 from the second opening 312 and retracted from the first opening 310. Referring to FIG. 7, the force of the actuating fluid pushes the piston 316 and the piston rod 318 towards the first end 306 of the cylinder barrel 304 in the second direction 323. As the first locking pin 354 is coupled to the piston rod 318 through the second shaft 384, the first locking pin 354 is also pushed away from the first side plate 204 in the second direction 323 causing the first locking pin 354 to disengage from the first side plate 204. FIG. 7 shows the first locking pin 354 disengaged from the first side plate 204. Sliding motion of the first locking pin 354 away from the first side plate 204 in the second direction 323 is restricted by abutting of the first lock nut 407 against the retraction stopper 366. As the piston rod 318 and the piston 316 are coupled with the first locking pin 354 through the second shaft 384, the piston 316 and the piston rod 318 cannot slide further towards the first end 306 of the cylinder barrel 304 in the second direction 323. The first coupling pin 378 is at the most extreme position possible towards the first side plate 204.

The actuating fluid is still supplied to the double acting cylinder 302 from the second opening 312 and retracted from the first opening 310. Now, force of the actuating fluid pushes the cylinder barrel 304 towards the second end 308 of the cylinder barrel 304 in the first direction 321. Sliding motion of the cylinder barrel 304 is restricted by the sliding motion of the first coupling pin 378 inside the first slot 332 and the second slot 334 defined by the pair of mounting brackets. FIG. 8 shows the first coupling pin 378 at the most extreme position possible away from the second side plate 206. The motion of the cylinder barrel 304 towards the second end 308 of the cylinder barrel 304 in the first direction 321retracts the first barrel cover 314 and the first shaft 344 towards the second end 308 of the cylinder barrel 304. As the second locking pin 356 is coupled to the first shaft 344, the second locking pin 356 is pushed away from the second side plate 206 causing the second locking pin 356 to disengage from the second side plate 206, thereby completely unlocking the mast 108 with the first and second side plates 204, 206 respectively and the chassis 102.

FIG. 9 shows another embodiment of the present disclosure. The locking mechanism 212 includes a trunnion 320 rigidly connected to the cylinder barrel 304. The trunnion 320 may be connected to the cylinder barrel 304 at any location between the first end 306 and the second end 308 of the cylinder barrel 304. In an embodiment, the trunnion 320 is connected to the cylinder barrel 304 such that the trunnion 320 is equidistant from the first end 306 and the second end 308 of the cylinder barrel 304. The trunnion 320 includes a frame member 322 rigidly coupled to the cylinder barrel 304, and partially enclosing the cylinder barrel 304. The frame member 322 may be connected to the cylinder barrel 304 by any suitable mechanical joining means such as welding. In an embodiment, the cylinder barrel 304 may be manufactured with the frame member 322 as an integral part. A first pin 324 and a second pin 326 are coupled to the frame member 322 on opposite sides of the frame member 322. Each of the first pin 324 and the second pin 326 may be a cylindrical pin coupled to the frame member 322, and extending away from the frame member 322 in opposite directions. The trunnion 320 may be machined from a single metal block, with integral frame member 322, and the first pin 324 and the second pin 326.

The double acting cylinder 302 is mounted on the base plate 202 through the trunnion 320. The trunnion 320 is further coupled to the pair of mounting brackets coupled to the base plate 202. The first pin 324 of the trunnion 320 slides inside the first slot 332 between the first end 336 and the second end 338 of the first slot 332. The second pin 326 of the trunnion 320 slides inside the second slot 334 between the third end 340 and the fourth end 342 of the second slot 334. The first pin 324 and the second pin 326 of the trunnion 320 engage the first slot 332 and the second slot 334 such that the pair of mounting brackets guides a sliding motion of the trunnion 320. The pair of mounting brackets also restricts an extent of sliding motion of the trunnion 320. As the trunnion 320 is rigidly connected with the cylinder barrel 304, the pair of mounting brackets also restricts an extent of sliding motion of the cylinder barrel 304. The trunnion 320 performs similar function as the first coupling pin 378 in defining the motion of the locking mechanism 212.

The locking mechanism 212 further includes a first self-alignment mechanism 346 coupling the first barrel cover 314 and the first shaft 344. The first self-alignment mechanism 346 accommodates a mismatch between axial alignments of the first barrel cover 314 and the first shaft 344, and allows the first barrel cover 314 to transfer axial forces to the first shaft 344 even if the first barrel cover 314 and the first shaft 344 are not in perfect axial alignment. The first self-alignment mechanism 346 includes a first coupling sleeve 348 which partially covers the first barrel cover 314 as well as the first shaft 344. A first sleeve pin 350 passes through the first coupling sleeve 348 and the first barrel cover 314, and a second sleeve pin 352 passes through the first coupling sleeve 348 and the first shaft 344. The first sleeve pin 350 and the second sleeve pin 352 are orthogonally oriented relative to each other. The first coupling sleeve 348 holds the first barrel cover 314 and the first shaft 344 together, and the first sleeve pin 350 and the second sleeve pin 352 couple the first barrel cover 314 and the first shaft 344 with the first coupling sleeve 348 respectively. The first barrel cover 314 may transfer an axial force to the first shaft 344 even when the first barrel cover 314 and the first shaft 344 are not in perfect axial alignment.

FIG. 10 illustrates another embodiment of the present disclosure. The locking mechanism 212 further includes a second self-alignment mechanism 1002 coupling the piston rod 318 and the second shaft 384. The second self-alignment mechanism 1002 accommodates a mismatch between axial alignments of the piston rod 318 and the second shaft 384, and allows the piston rod 318 to transfer axial forces to the second shaft 384 even if the piston rod 318 and the second shaft 384 are not in perfect axial alignment. The second self-alignment mechanism 1002 includes a second coupling sleeve 1004 which partially covers the piston rod 318 as well as the second shaft 384. A third sleeve pin 1006 passes through the second coupling sleeve 1004 and the piston rod 318, and a fourth sleeve pin 1008 passes through the second coupling sleeve 1004 and the second shaft 384. The third sleeve pin 1006 and the fourth sleeve pin 1008 are orthogonally oriented relative to each other. The second coupling sleeve 1004 holds the piston rod 318 and the second shaft 384 together, and the third sleeve pin 1006 and the fourth sleeve pin 1008 couple the piston rod 318 and the second shaft 384 with the second coupling sleeve 1004 respectively. The piston rod 318 may transfer an axial force to the second shaft 384 even when the piston rod 318 and the second shaft 384 are not in perfect axial alignment.

INDUSTRIAL APPLICABILITY

The present disclosure provides a method 1100 of locking the mast 108 with the first side plate 204 and the second side plate 206. FIG. 11 illustrates a flow chart for the method 1100. At step 1102, the actuating fluid is supplied to the first opening 310 of the double acting cylinder 302. The double acting cylinder 302 includes the cylinder barrel 304. The piston rod 318 coupled to the piston 316 slides inside the cylinder barrel 304. Subsequently, the second shaft 384 coupled to the piston rod 318 slides accordingly. At step 1104, the first locking pin 354 coupled with the second shaft 384 is moved to engage the first side plate 204 through the movement of the second shaft 384 due to force applied by the actuating fluid.

At step 1106, the second locking pin 356 coupled with the double acting cylinder 302 at the first end 306 of the cylinder barrel 304 is moved to engage the second side plate 206 through the movement of the cylinder barrel 304. The cylinder barrel 304 has the first barrel cover 314 coupled to the cylinder barrel 304 at the first end 306 of the cylinder barrel 304. The first shaft 344 couples the first barrel cover 314 of the cylinder barrel 304 to the second locking pin 356. The first barrel cover 314 and the first shaft 344 are coupled through the first coupling mechanism 370 to accommodate any misalignment between the first barrel cover 314 and the first shaft 344. The mast 108 is locked when the first locking pin 354 and the second locking pin 356 are engaged with the first side plate 204 and the second side plate 206 respectively. It should be contemplated that the step 1104 and the step 1106 may occur simultaneously, or the step 1106 may occur before the step 1104 based on seal friction or any other such internal frictional forces between various components.

The method 1100 of the present disclosure further includes steps for unlocking the mast 108. Steps for unlocking the mast 108 are described with help of a flow chart 1200 in FIG. 12. Step 1202 includes supplying the actuating fluid to the second opening 312 of the double acting cylinder 302. Step 1204 includes moving the first locking pin 354 coupled with the second shaft to disengage from the first side plate 204 through the movement of the second shaft 384. The second shaft 384 is coupled to the piston rod 318, and slides along with the piston 316 and the piston rod 318 towards the first end 306 of the cylinder barrel 304. The extent of sliding motion of the first locking pin 354 is restricted by the retraction stopper 366.

Step 1206 includes moving the second locking pin 356 coupled with double acting cylinder 302 to disengage from the second side plate 206 through the movement of the cylinder barrel 304 of the double acting cylinder 302. The mast 108 is unlocked when the first locking pin 354 and the second locking pin 356 are disengaged with the first side plate 204 and the second side plate 206 respectively. It should be contemplated that the step 1204 and the step 1206 may occur simultaneously, or the step 1206 may occur before the step 1204 based on seal friction or any other such internal frictional forces between various components.

The locking mechanism 212 and the method 1100 of locking and unlocking the mast 108 provided by the present disclosure solves the problems posed by the locking mechanisms of the prior art. The locking mechanism 212 makes use of only one double acting cylinder 302, to emulate the functions of two double acting cylinders and requires lower part count as compared to prior art solutions. Further, using only one double acting cylinder 302 requires only one set of sealing arrangements for the hydraulic circuitry. Further, only one set of hose routings may be necessary for supplying the actuation fluid to the double acting cylinder 302. The reduced part count leads to a simpler locking mechanism 212 which is easier to use as compared to prior art systems. Also, cost of the locking mechanism 212 may also get reduced due to the lower part count required. Reduction in costs may further contribute towards increasing overall efficiency of the machine 100.

While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machines, systems and methods without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof. 

What is claimed is:
 1. A locking mechanism for locking a mast of a rotary drill, the locking mechanism comprising: a double acting cylinder, wherein the double acting cylinder comprises: a cylinder barrel having a first end and a second end; a first barrel cover coupled to the cylinder barrel at the first end, the first barrel cover including: a cover adapted to be coupled to the cylinder barrel at the first end; and a barrel cover shaft coupled to the cover, wherein the barrel cover shaft includes a first surface defining a first aperture; a second barrel cover coupled to the cylinder barrel at the second end; a piston adapted to perform a sliding motion inside the cylinder barrel between the first end and the second end; and a piston rod coupled to the piston, the piston rod adapted to slide in a first direction and a second direction relative to the second end of the cylinder barrel; a first coupling mechanism for coupling the first barrel cover to a first shaft towards the first end of the cylinder barrel, wherein the first coupling mechanism includes: a first cover member having a first cover surface defining a first coupling pin hole, and a first shaft opening adapted to receive the first shaft therein; and a first coupling pin passing through the first coupling pin hole and the first aperture of the barrel cover shaft such that the first coupling pin couples the first cover member and the barrel cover shaft, wherein the first coupling pin has a first end and a second end extending out from the first coupling pin hole; a pair of mounting brackets coupled to a base plate of the mast, the pair of mounting brackets comprising: a first mounting bracket having a first bracket surface defining a first slot, wherein the first slot has a first end and a second end; and a second mounting bracket having a second bracket surface defining a second slot, wherein the second slot has a third end and a fourth end; wherein the first slot allows the first end of the first coupling pin to slide inside the first slot between the first and second ends of the first slot, and the second slot allows the second end of the first coupling pin to slide inside the second slot between the third and fourth ends of the second slot such that a sliding motion of the first coupling pin, and subsequently a sliding motion of the cylinder barrel is guided by the first slot and the second slot; a first locking pin connected to the piston rod, and adapted to selectively engage a first side plate based on the sliding motion of the piston rod; a retraction stopper mounted on the base plate of the mast, wherein the retraction stopper is adapted to restrict an extent of sliding motion of the first locking pin in a second direction, and adapted to subsequently cause a movement of the cylinder barrel in the first direction; a second locking pin connected to the first shaft, and adapted to selectively engage a second side plate based on the movement of the cylinder barrel; wherein the mast of the rotary drill is locked when the first locking pin and the second locking pin are engaged with the first side plate and the second side plate respectively; and wherein the mast of the rotary drill is unlocked when the first locking pin and the second locking pin are disengaged with the first side plate and the second side plate respectively.
 2. The locking mechanism of claim 1, further comprising a second shaft coupled to the piston rod towards the second end of the cylinder barrel such that the second shaft transfers motion of the piston rod to the first locking pin.
 3. The locking mechanism of claim 2, wherein the second shaft is coupled to the piston rod through a second coupling mechanism, the second coupling mechanism includes: a second cover member having a second cover surface defining a second shaft opening adapted to receive the second shaft therein; and a second coupling pin passing through the second cover member and the second aperture in a piston rod surface defined by the piston rod such that the second coupling pin couples the second cover member and the piston rod.
 4. The locking mechanism of claim 1, wherein the first locking pin locks with a first lock nut at one end to selectively restrict an extent of movement of the first locking pin in the second direction by abutting against the retraction stopper.
 5. The locking mechanism of claim 1, wherein at least one mounting bracket from the pair of mounting brackets is coupled to the base plate by a mechanical fastener.
 6. The locking mechanism of claim 1, wherein at least one mounting bracket from the pair of mounting brackets is welded to the base plate.
 7. The locking mechanism of claim 1, wherein the first side plate has a surface defining a plurality of angularly spaced openings such that in a locked condition the first locking pin slides into one of the plurality of angularly spaced openings to engage the first side plate to lock the mast in a corresponding angular position.
 8. The locking mechanism of claim 1, wherein the second side plate has a surface defining a plurality of angularly spaced openings such that in a locked condition the second locking pin slides into one of the plurality of angularly spaced openings to engage the second side plate to lock the mast in a corresponding angular position.
 9. A rotary drill comprising: a chassis supported over a ground engaging mechanism; a first side plate coupled to the chassis; a second side plate coupled to the chassis; a mast provided between the first side plate and the second side plate; a base plate coupled to the mast towards a bottom end of the mast; and a locking mechanism for locking the mast with the first side plate and the second side plate, the locking mechanism comprising: a double acting cylinder, wherein the double acting cylinder comprises: a cylinder barrel having a first end and a second end; a first barrel cover coupled to the cylinder barrel at the first end, the first barrel cover including: a cover adapted to be coupled to the cylinder barrel at the first end; and a barrel cover shaft coupled to the cover, wherein the barrel cover shaft includes a first surface defining a first opening; a second barrel cover coupled to the cylinder barrel at the second end; a piston adapted to perform a sliding motion inside the cylinder barrel between the first end and the second end; and a piston rod coupled to the piston, the piston rod adapted to slide in a first direction and a second direction relative to the second end of the cylinder barrel; a first coupling mechanism for coupling the barrel cover to a first shaft towards the first end of the cylinder barrel, wherein the first coupling mechanism includes: a first cover member having a first cover surface defining a first coupling pin hole, and a first shaft opening adapted to receive the first shaft therein; and a first coupling pin passing through the first coupling pin hole and the first aperture of the barrel cover shaft such that the first coupling pin couples the first cover member and the barrel cover shaft, wherein the first coupling pin has a first end and a second end extending out from the first coupling pin hole; a pair of mounting brackets coupled to a base plate of the mast, the pair of mounting brackets comprising: a first mounting bracket having a first bracket surface defining a first slot, wherein the first slot has a first end and a second end; and a second mounting bracket having a second bracket surface defining a second slot, wherein the second slot has a third end and a fourth end; wherein the first slot allows the first end of the first coupling pin to slide inside the first slot between the first and second ends of the first slot, and the second slot allows the second end of the first coupling pin to slide inside the second slot between the third and fourth ends of the second slot such that a sliding motion of the first coupling pin, and subsequently a sliding motion of the cylinder barrel is guided by the first slot and the second slot; a first locking pin connected to the piston rod, and adapted to selectively engage the first side plate coupled to the chassis based on the sliding motion of the piston rod; a retraction stopper mounted on the base plate of the mast, wherein the retraction stopper is adapted to restrict an extent of sliding motion of the first locking pin in the second direction, and adapted to subsequently cause movement of the cylinder barrel in the first direction; a second locking pin connected to the first shaft, and adapted to selectively engage the second side plate coupled to the chassis based on the movement of the cylinder barrel; wherein the mast of the rotary drill is locked when the first locking pin and the second locking pin are engaged with the first side plate and the second side plate respectively; and wherein the mast of the rotary drill is unlocked when the first locking pin and the second locking pin are disengaged with the first side plate and the second side plate respectively.
 10. The rotary drill of claim 9, further comprising a second shaft coupled to the piston rod towards the second end of the cylinder barrel such that the second shaft transfers motion of the piston rod to the first locking pin.
 11. The rotary drill of claim 10, wherein the second shaft is coupled to the piston rod through a second coupling mechanism, the second coupling mechanism includes: a second cover member having a second cover surface defining a second shaft opening adapted to receive the second shaft therein; and a second coupling pin passing through the second cover member and a second aperture in a piston rod surface defined by the piston rod such that the second coupling pin couples the second cover member and the piston rod.
 12. The rotary drill of claim 9, wherein the first locking pin locks with a lock nut at one end to selectively restrict an extent of movement of the first locking pin in the second direction from the first side plate by abutting against the retraction stopper.
 13. The rotary drill of claim 9, wherein at least one mounting bracket from the pair of mounting brackets is coupled to the base plate by a mechanical fastener.
 14. The rotary drill of claim 9, wherein at least one mounting bracket from the pair of mounting brackets is welded to the base plate.
 15. The rotary drill of claim 9, wherein the first side plate has a surface defining a plurality of angularly spaced openings such that in a locked condition the first locking pin slides into one of the plurality of angularly spaced openings to engage the first side plate to lock the mast in a corresponding angular position.
 16. The rotary drill of claim 9, wherein the second side plate has a surface defining a plurality of angularly spaced openings such that in a locked condition the second locking pin slides into one of the plurality of angularly spaced openings to engage the second side plate to lock the mast in a corresponding angular position.
 17. A method for locking a mast of the rotary drill, the method comprising; supplying an actuating fluid to a first opening of a double acting cylinder, wherein the double acting cylinder has a cylinder barrel, and a piston rod coupled to a piston adapted to slide inside the cylinder barrel; moving a first locking pin coupled with the piston rod, through the movement of the piston rod due to force applied by the actuating fluid, to engage a first side plate; and moving a second locking pin coupled with the double acting cylinder, through the movement of the cylinder barrel of the double acting cylinder, to engage a second side plate, wherein the mast of the rotary drill is locked when the first locking pin and the second locking pin are engaged with the first side plate and the second side plate respectively.
 18. The method of claim 17 further comprising: supplying the actuating fluid to a second opening of the double acting cylinder; moving the first locking pin coupled with the piston rod, through the movement of the piston rod, to disengage from the first side plate, wherein an extent of motion of the first locking pin is restricted by a retraction stopper; and moving the second locking pin coupled with the double acting cylinder, through the movement of the cylinder barrel of the double acting cylinder, to disengage from the second side plate, wherein the movement of the cylinder barrel is restricted by abutment of the first coupling pin with the first end of the first slot and the third end of the second slot, and wherein the mast of the rotary drill is unlocked when the first locking pin and the second locking pin are disengaged with the first side plate and the second side plate respectively.
 19. The method of claim 18, wherein moving the second locking pin coupled with the double acting cylinder further comprises: moving the second locking pin, through the movement of the cylinder barrel, wherein the cylinder barrel is coupled to the second locking pin through a first shaft.
 20. The method of claim 17, wherein moving the first locking pin coupled with the piston rod further comprises: moving the first locking pin, through the movement of a second shaft, wherein the second shaft couples the piston rod with the first locking pin. 